- Mild and chemoselective lactone ring-opening with (TMS)ONa. Mechanistic studies and application to sweroside derivatives
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Mild and chemoselective opening of lactones with sodium trimethylsilanolate in high yields and aprotic solvents is described. Kinetic studies demonstrate that the BAc2 mechanistic pathway is followed. Nucleophilic attack of silanolate onto the carbonyl of the lactone moiety is the rate-determining step. NaOH present as an impurity accelerates the reaction. The method was further applied to the base-sensitive and stable lactones derived from highly functionalized iridoid derivatives.
- Lemoine, Hugues,Markovi?, Dean,Deguin, Brigitte
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p. 4358 - 4366
(2014/06/09)
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- Process for preparing peroxides using mixed anhydrides
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The invention relates to a process for the preparation of a peracid, perester or diacylperoxide and is characterized in that a mixed anhydride of formula R1[C(O)OC(O)OR2]nor [R3C(O)OC(O)O]pR4/su
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- CARBOXYLATED PHOSPHATIDIC ACID ESTERS
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Novel compounds of formula in which R1 and R2 are phospholipid fatty acid residues and A is an aliphatic and/or cycloaliphatic hydrocarbon chain optionally substituted by hydroxy and/or further carboxylic functions. The novel compounds are useful for making liposomes of enhanced stability and entrapping capacity.
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- Process for the production of epothilones and intermediate products within the process
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The invention relates to a process for the production of epothilones and intermediate products within the process. Epothilones A and B are natural substances, which can be produced by microorganisms, and the taxols have similar properties and are thus of particular interest in pharmaceutical chemistry.
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- Development and Evaluation of Antisera for Detection of the O,O-Diethyl Phosphorothionate and Phosphorothionothiolate Organophosphorus Pesticides by Immunoassay
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An immunochemical approach for class detection of organophosphorus pesticides was investigated. Synthesis of O,O-diethyl phosphorothionate haptens and their use in the generation of polyclonal antisera are described. An indirect inhibition format ELISA co
- Johnson, Jeffre C.,Van Emon, Jeanette M.,Pullman, Diane R.,Keeper, Kenneth R.
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p. 3116 - 3123
(2007/10/03)
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- 2-[1-(1,3-thiazolin-2-yl)azetidin-3-yl]thio-carbapenem derivatives
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Novel carbapenem compounds, (1R,5S,6S)-2-[1-(1,3-thiazolin-2-yl)azetidin-3-yl]thio-6-[(R)-1-hydroxyethyl]-1-methyl-carbapen-2-em-3 -carboxyic acid derivatives. These carbapenem compounds are represented by the following formula having a beta-coordinated methyl group introduced at the 1-position and a [1-(1,3-thiazolin-2-yl)azetidin-3-yl]thio group introduced at the 2-position. STR1 In the formula, R is hydrogen; lower alkyl group which is unsubstituted or substituted by hydroxy, lower alkoxy or lower alkoxy-lower alkoxy group; group --COOR1 (R1 is hydrogen or lower alkyl group); or group --CONR2 R3 (R2 and R3 are, independently each other, hydrogen or lower alkyl), and Y is carboxy, --COO? or protected carboxy. These compounds are useful antibiotics for prevention and treatment of bacterial infections.
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- 9-Substituted carbacyclin analogs
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Novel compounds of the following general formula: STR1
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- Synthesis of 9-Substituted Carbacyclin Analogues
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The synthesis of a series of 9-substituted carbacyclin analogues with potent platelet antiaggregatory activity is described.The key step for the formation of 9-acetylene compounds (e. g., 8d) utilized a modification of the Schwartz procedure involving the nickel-catalyzed conjugate addition of the appropriate alkynyl aluminate to bicyclooct-1-en-3-one (2).It was found that 9-methylcarbacyclin (8b) could be prepared by a similar procedure.In addition, a novel alternative to the Wittig reaction for introducing the carbacyclin upper side chain in base-sensitive substrates was developed which involves the addition of the dianion of 6-((tert-butyldimethylsilyl)oxy)hexanoic acid to the appropriate ketone (e. g., 6f or 2) followed by decarboxylative dehydration of the resulting β-hydroxy acid.
- Aristoff, Paul A.,Johnson, Paul D.,Harrison, Allen W.
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p. 5341 - 5348
(2007/10/02)
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